Refrigerating system



P. scHLUMBoHM 2,111,904

2 Sheets-Sheet 1` March 22, 1938..

I HEFRIGERATING SYSTEM 2 Sheets-Sheet 2 March 22, 1938. P. s'cHLUMBoHM REFRIGERATING SYSTEM Filed Nov. 19, 1952 Patented Mar. 22, 1938 UNITED STATES .PATENT OFFICE Peter Schlnmbohm, Berlin, Germany Application Niwambcr 1s, 1932, serial-No. 343,344

In Germany November 25, 1931 16 Claims.

The purpose of my invention is to improve water ice cooling systems by the combined use of water ice and power, especially electric power. This new procedure is more economicalfor the Iconsumer of the cold than the exclusive use of power as usual in entirely mechanical refrigerators.

The invention relates to improved refrigeration systems in which the ordinary commodity,

water ice, is combined with refrigerating apparatu's of the compression type in which the cold i l. is produced by the evaporation of a refrigerant,

the vapors of. which become liquefied again by means of a compressor, and to improved methods of refrigeration and refrigerators utilizing such systems. In a particular embodiment, the

new refrigerating system is characterized by the may also secure all the advantages of water ice refrigeration. It is therefore obvious that the invention opens up new iield for the water ice industry and enables it eifecti-vely to meet competition iby entirely mechanical refrigerators One object of my invention is to provide methods and apparatus by which temperaturesbelo'w the freezing point of water may be produced although the caloriiic. effect is derived from ordinary water ice. Another object is to provide improved ice boxes or refrigerators in which refrigerating apparatus of the compression type is utilized in combination with water ice -so that advantages of both are obtained, while individual disadvantages of each, from both an economic and technical point of view, are avoided.

I am awarev of the fact that it is known to cool the condenserof a refrigerating system by the cold evaporator of another refrigerating machine. This arrangement has been made in order to produce extremely low temperatures. However, this is not the aim of my invention, which aims only at temperatures sumciently low for freezing or storing ice cream, e. g. 10 C.,-

i temperatures that heretofore have i not been (ci. 'sz-115) cludes in combination, a compressor, a condenser and an evaporator. 'I'he compressor may be one having a low-compression ratio, that is about 1:2 rather than that which is usual in compression systems, namely 1:5 or even 1:6, and hence more economical than that found in normal mechanical refrigerating practice. This small compression corresponds to the .relation between the saturated pressure of the refrigerant near the freezing point of water, this temperature being maintained by the water ice cooled condenser, andthe saturated pressure of the refrigerant in the evaporator at the temperature of e. g. about 10 centigrade.

The low ratio of compression utilized allows a simplication of the compression system by the use of a cheap compressor, e. g. of the blower type, and further by the use of liquid traps insteadl of complicated valves for shutting oi .the condenser from the evaporator and for bringing the liqueed refrigerant from the condenser back to the evaporator. The expression low ratio compressor as used in the claims is to be understood as defining such `a compressor, that is to say, one having a ratio not greater than 3 to 1.

'I'he invention is illustrated by way of exemi plication in the accompanying drawings.

Fig. 1Flg. 3 illustrate the new system partly in perspective and partly in section as installed in a refrigerator of the ice box type.

In Figs. 1 to 3 the compression system comprises in combination the compressor I, the evaporator 2, the condenser 3, and connecting pipes including pipe 4 between. compressor and con-'- denser, pipe 5 between the evaporator and the compressor," andI pipe 6 between the condenser and the evaporator. In Figs. 1 to 3 the condenser 3 is preferably built as a double walled container. The inside of the container or cooling space 1 is'fllled with ice 8, and the space between the double walls of the container 'I forms the condensing space 3.

In Fig. 1 the compression system is installed in a refrigerator 9, the refrigerator 8 being dicompartment is cooled by the refrigerant i5,

I is started. The refrigerants employed are those which are useful in the refrigerating art, for example, ammonia, sulfurl dioxide, methyl chloride, ethyl chloride, and others.

'Ihe exemplification as shown in Fig. 2 shows the ice container 1 together with the condenser 3, insulated by a special jacket, and positioned outside of the refrigerator 9, which in this case is cooled exclusively by the refrigerant I5. The connecting pipe 6 between the condenser 3 and the evaporator 2 is formed in the shape of a U in order to allow the liquid refrigerant I5 to form a liquid trap and a column S, thus separating the domain of higher pressure in the condenser from the domain of lower pressure in the evaporator.

In Fig. 3 an apparatus is shown which forms a constructional unit, comprising the compressor I, the ice container 1, the condenser 3, the evaporator 2, and the connecting pipes 4, 5, and 6. The unit thus formed may be removably placed inside of the refrigerator 9. T'he construction as shown in Fig. 3 includes an evaporator 2 which is formed as a double walled container, the inside of which is equipped as a refrigerating chamber II e. g. for the freezing and storing of ice creami. The outside of the double walled evaporator 2 is surrounded by aheat insulating jacket I0.- In this case the refrigerator 9 ls cooled by the ice container I only, and the come pressor I is started only occasionally when it is desired to use the refrigerating chamber for the storing or for the making of ice cream.

Having now described the 4various exemplifi` penetrate the walls of the cooling room in order to arrange the cold developing parts of the machine inside of the cooling room and to place the heat developing parts of the refrigerator outside of the cooling room. The new apparatus can be placed entirely and even remiovably, as shown especially in Fig. 3, inside of the cooling room. 'I'his is particularly important for transportable cooling rooms, refrigerator cars and trucks. Furthermore, this factor makes it easy to equip subsequently a normal water ice box of the old system with the apparatus of the invention.

I yhave found it to be practical to provide means for allowing the vapors of the refrigerant to flow from the evaporator to the condenser even while the compressor is not working. Accordingly a compressor with a small compression ratio can be used, for instance, a centrifugal blower. It will be realized that this blower, while not working, allows the vapors to flow from the evaporator through the suction tube, through the blower and through the pressure tube into the condenser. 'I'he practical advantage is that when the compressor is not working vthe temperature in the evaporator does not rise considerably higher than the temperature of the condenser owing to the evaporation of refrigerant taking place when the temperature in the evaporator becomes higher than the temperature in the condenser.

user of such an ice box is able to secure humid refrigeration of the kind supplied by water ice, or, as desired, the more intense refrigeration or freezing effects of an evaporating refrigerant. Because of the refrigerating effect of the water ice, to secure subfreezing temperatures does not require that the entire heat load of the box be carried away by the evaporator-compressor system. When not needed, operation of the compression apparatus may be discontinued, in which event the water ice serves effectively to maintain entirely satisfactory temperature conditions for preserving foodstuffs. Furthermore, by employing open circulation of the refrigerant from the evaporator to a point in heat exchange with the Water ice and thence back to the evaporator, temperatures sufficiently low for many purposes may also be maintained in the chamber or compartment wherein the evaporator is located.

I wish to emphasize that cooling the condenser with water ice is a feature of my invention which is employed only to obtain the optimumi technical solution. The new ice box is superior to entirely mechanical refrigerators or ice boxes cooled only by water ice when it is provided With an air cooled compression refrigerating apparatus in combination with water ice.

After having thus described the nature of my invention and in what manner the same is to be performed, what I claim is:

1. The method of operating a refrigerator which consists in simultaneously absorbing the heat of the storage space and the contents thereof by melting a renewable charge of water ice within said space and cooling a heat insulated zone Within said space to a sub-freezing temperature by evaporating a second refrigerant within said zone.

2. The method of operating a.l refrigerator, which consists in simultaneously absorbing the heat of the storage space and the contents thereo'f by melting externally produced water ice within said space and cooling a heat insulated zone within said space to a sub-freezing temperature by evaporating a second refrigerant within said zone.

3. The method of improving the economy of a mechanical refrigerating system in which the evaporator operates in a heat-insulated zone at low temperatures to freeze substance in said zone, which comprises reducing the heat load to be taken up by the evaporating refrigerant to approximately the net heat load extracted from the substance to be frozen by shielding said zone against additional outside heat flowing thereto by means of externally produced water ice in an outer heat-insulated zone.

4. A cooling system for the use of water ice and a temperature transformer of the compression type in functional relation to each other, said transformer having an evaporator, a condenser, a mass of water ice in `heat exchange with the condenser and a-low`ratio compressor arranged between evaporator and condenser in functional relation thereto, the working ratio of said compressor being such that said transformer is operative to evaporate a refrigerant in the evaporator at temperatures below the melting point of ice only when the vapors ofsaid refrigerant are compressed by said compressor and condensed in heat exchange with said water ice.

5. A cooling system as definedl in claim 4, wherein a U-shaped .conduit is connected between an evaporator and a condenser and the difference in the pressures thereof is balanced by a difference in level of said refrigerant in the U-shapcd conduits. f

6. An ice box comprising a heat insulated casing enclosing a cooling. compartment and\the evaporator of a compression refrigerating machine having a condenser arranged outside said compartment and a compressor, a heat insulated chamber outside of said compartment forstoring `a mass of ice, and means to cool said cooling` compartment by` heat exchange with said ice when the compressor is not operating.

l'7. The method of operating a refrigerating apparatus of the ice box type having a chamber and ice holding means therein and a second chamber. which method comprises cooling the rst mentioned chamber by heat exchange ,with water ice and cooling the secondA chamber by means of areirigerating unit of the compression type while cooling heat developing parts oi the latter by heat exchange with water ice.

8. In a refrigerating system of the ice-box type `using water ice as the cooling agent and having two cooling chambers one maintained at a temperature above and one maintained at a tem- `perature fbelow the temperature of melting waparatus, said apparatus including,l a condenser mechanism arranged; to hold: water ice in. heat. exchange relation to compressed refrigerant; and also in position to cool said interior, and a secondary rei'rigerating system including said condenser, an evaporator arranged m said interior, and a compressor and means connecting the compressor to the evaporator and the condenser.

10. A structure' of the type Speciiled in claim 9 in which said interior is divided into separate compartments and'said condenser mechanism is disposed in one compartment and said evaporator in another compartment.

11. A structure ofthe type specied in claim 9 in which said evaporator comprises a device adapted to maintain atemperatme below that of melting water ice and -includes an insulated exterior wall enclosing a space for goods to be cooled and a closure for said space.

12. In a refrigerating system of the type using water ice as the main cooling agent, the combination withl a cooling chamber of a condenser adapted to hold water ice in heat exchange relation with the cooling chamber and arranged to provide a substantial portion ofthe cooling. of

the cooling chamber, and a refrigerating unit providing a region at a vtemperature lower than that of the Water ice and comprising a compressor, said condenser andan evaporator, the water ice forming the denser.

13. A refrigerating apparatus of the ice box type comprising a casing having upper and lower compartments, tubular means associated with the upper compartment adapted to hold water ice in heat exchange relationr with said upper comcondensing medium for the conpartment, a..coo1ing unit comprising a .condenser associated with and forming a part of said tubular means, an evaporator in heat exchange. relation with said lower compartment and a compresser connected tok said evaporator and condenser.

14. A, refrigerating apparatus as deined in .claim 13, wherein the compressor is a. low ratio compressor:

15. A structure of the type described compris-i l ing the combination of a refrigerator device hav ing an interior to be cooled anda refrigerating apparatus', said apparatus: including, a condenser mechanism arranged to hold water ice. in heat exchange,- relation to: compressed refrigerant and also inV position to cool said interior, and a secondary refrigerating system including said condenser, an evaporator arranged in said interior, and ac compressonand means connecting the compressor to the? evaporator and the condenser, and means connecting the condenser to the evaporator.

16. A reirigerating apparatus of the ice `boi: 

